Trialkyl 9(10)-phosphonostearates as plasticizers for vinyl chloride polymers



United States Patent No. 35,858 g 6 Claims. (Cll 260--30.6)- (Granted under Title35; U.'S: C0de'( 1952),- 'sec." 266) A non-exclusive, irrevocable,.royalty-rfree license in'the invention herein described,.throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such-purposes-,*ishereby: (granted to the Government. of the United. States. of.

America.

This application is a division of application bearing Serial No. 814,357, filed May 19, 1959, now Patent No.

Thisinvention: relates to the preparation of. trialkyl 9.( phosphonostearates and to compositions contaim ing these new phosphorus derivatives.

An object of this invention is to prepare-alkyl piles-*- phonate derivatives-ofan ester of a fatty acid-which contains an isolated, relatively unreactive" ld-ouble'bondl Another object is to-p-repare efiieient lowtemperatu-re' plasticizers for polymers such as poly(viny1 chloride); A iurther object is to prepare low temperature plasticizers which have unusually low migration characteristics.

Other objects and a fuller understanding of the inven-f tion may be had by referring to the following description and claims. 7 p,

According to the. present invention trialkyl. phosphonost-earates'of the general. formula V "ice atoms, such as methyl oleate, ethyl oleate, n-butyl oleate, or Z-ethylhexyl oleate at a temperature of at least about 1 00" (3. in the presence of a decomposing peroxide having a "life long enough to give activating species duriugithe reaction period, such as tertiary butyl perbenzoate, and under an atmosphere of an inert gas, for example, nitrogen, until the reaction is complete.

Under the described conditions substantially; quantitative yields of product are obtained in a few hours.

Theproduct'is a mixture of the 9- and 10 dialk yl phosphonate derivatives, since no selective addition efiects are operative, the optionalpo'sitions being shown inlthe gerieral formula by theme of the-subscript (1'5-x) where x'is 7 or 8.

The trialkyl 9(10)=phosph0nostearatesare readily coinpatible with vinyl chloride polymers andare 'efiicientlowtemperature plasticizers for these polymers. 'For ex ample, when one of these. polymers is plasticizedr with about by weight, of one of:thesephosph onostearates, a flexible composition containing this amount of plasticizer is produced. This mayv-beseen by reference to Examples 9-13 hereinafter. Moreover, the compounds of this invention are-outstanding in-that they: have a low and .constantmigrationloss, only, 8'-9% as compared-with23 loss'dor diQZ-ethy-lhexyl) sebacate.

Preparation of alkyl oleates.These are prepared in the-conventionalmanner, as illustrated. Methyl-and ethyl oleate were-prepared:by'refluxing oleic acid (a low linoleic-grade) with a 5-molar excessof' absolute methanol or'ethanol, using naphthalene2-sulfonic acid ascatalyst.

wherein R and R'are allylradicals containing 1 to: 8'-

carbon atoms and xis-a'number' select'edtrom-the group consisting of 7 and 8-, are prepared by a processcomprisiug reacting a 'dialkylphosphonatehavingthetorrnula wherein R is an alkyl radical. containing. 11. to.'- 8 carbon.

atoms, such as. dimethyliphosplronate, diethyl phosphoriate, ldi n-butyl phosphonate; or di-(Qethylhexyl) phos phonate with an alkyl oleaterhaving, thecformula CH (CH2) qCH: CH(CH 600R- wherein R is an alkyl radical containing 1 to 8 carbon trialkyl 9( 10)-phosphonostearates; All reactionsand dis Afiter several water washes, hollowed by drying over anhydrous sodium sulfate, the esters were-fractionally distilledmnder.diminishedpressure.

The n-butyl and 2- ethylhexyl oleates were prepared with azeotropic distillationof water; as describedby D.

Swernetal l Am. Chem. Soc, 67, 902. (1945). The

butyl alcoholwas the bestavailable commercial grade and. the. Z-ethylhexyl alcohol was a redistilled rfraction, B.P. 183-184' 0.. These. esters were also tractionally distilled.

l Fractionation ofdialkyl. ph0sph0nates.ConunerciaJllyavailablerdialkyl phosphonateswere distilled toobtainthe followingpure fractions: :dimetl'iyl'phosphonate, B.P. 72 C. at 25 mm. mercury pressure; diethylphosphonate, B.P. 73 C. at 10 mm.; di-n-butyl phosphonate, B.P. 64 C. at 0.0 5 mm.; and di-2-ethylhexyl.phosphonate, B.P. 128- 130 C. at 0.1 mm.

The following examples illustrate the preparation of tillations were conducted in' an atmosphere of nitrogen.

. EXAMPLE 1 Methyl oleate (0.2 mole), dimethyl .phosphonate: (0.6

. mole) and: 01005 mole of tertiary'butyl .perbenzoatewere combined in a 500 ml.- ronnd-bottomed flask equipped witha-rna'gnetic stirrer anda nitrogen inlettube. The

reaction was stirred and heated at.100-1-10 C. cfior- 4 hours.

reaction mixture was distilled under diminished pres- Patented Aug. 20,. 1963 Additional paroxide (0.005: mole), 'was added afterZhours elapsed time to facilitatethe-reaction. The

sure to recover excess dimethyl phosphonate. Total yield of crude trimethyl 9(10)-phospl10nostearate was substantially quantitative. This product was distilled and a traction having a uniform boiling point of 130 C. at 0.001 mm. (representing a 68% yield) was retained for analytical determinations (cf. Table I) and tor evaluation as a plasticizer.

peroxide, give unsatisfactory yields at the reaction temperatures employed.

The preferred temperature is about 100 C. or higher. At temperatures mum below 100 C. the addition is impractically slow. At a temperature in the range of 100 to 110 C. in the presence of t-butyl perbenzoate the reaction is complete in 4 hours, perhaps sooner in many Table l TRIALKYL 9(10)-PHOSPHONOSTEARATES B (u) CHa-(O11a)(15X CH-(OH2) X CO R R O-PO R l O (z=7 or 8) Y B.P Phosphorus Molecular Example Yield, refraction No. R R percent M (14 C. Mm Calcd. Found Calcd. Found 1 CH3; CH1 68 130 0. 001 1. 4531 0. 9889 7.6 7. 3 111. 9 111. 2 2 Cal? can 75 140 0. 001 1. 4492 O. 9596 6. 9 7. 125. 8 125. 4 3 ll-CAHO ri-CiTi'o 66 170 0. 001 1. 4502 0- 9372 5. 8 5. 9 153. 7 152.8 4:: 2-ethylhexy1 2-ethyll1cxy1 67 200 0.002 1. 4555 0. 9148 4. 4 4. 4 209. 4 208.2 5 Calls n-CIH'n 77 155 0. 001 1. 4504 0. 9435 6. 1 0. 2 144. 4 143. 9 6 n-CiHn Cq'FTr 67 150 O. 001 1. 4489 0. 9473 6. 5 6. 3 135. l 134. 9 7: 2ethylhcxyl C 11 68 170 O. 001 1- 4512 0- 9362 5. 8 5. 5 153. 7 153. 3

All'ot these compounds were distilled in a molecular still. Analytically pure fraction.

EXAMPLES 2 TO 7 5 instances as the progress of the reaction was not always Using the reaction conditions of Example 1, the remaining trialkyl phosphonostearates listed in Table I were prepared from the corresponding diialkyl phosphonates and alkyl oleates.

All the 9(10) -phosphonostearates of Table I are colorless, high-boiling, thermally stable liquids, insoluble in water and soluble in organic solvents. Pertinent anailytical data regarding the products are presented in Table 1.

While the examples cited do not cover all the possible combinations of alkyl substituents available from the reactants used it is readily apparent that methyl'dibutylphosphonostearate, ethyl dimethylphosphonostearate, etc. may be prepared by the reaction of this invention by the proper choice of oleate ester and dialkyl phosphonate. It is considered that numerous dialkyl phosphonates, such as dipropyl phosphonate, dihexyl phosphonate, di-n-octyl phosphonate, etc., will react, under conditions described in Example 1, with a variety of alkyl oleates to give many more trialkyl 9'(l0)-phosphonostearates. Dialkyl phosphonates with longer chain alkyl groups also would be expected to react under the conditions described.

EXAMPLE 8 The process of Example 1 was repeated with the exception that no t-butyl perbenzoate was added, but an attempt was made to catalyze the reaction by irradiation at a distance of 1 inch by a 140-watt ultraviolet lamp (high pressure quartz mercury arc). The mixture yielded only unchanged reactants.

Not only is the presence of a decomposing peroxide necessary to promote the reaction of a dialkyl phosphonate with an alkyl oleate, but the choice of peroxide is important. The half-life of the peroxide should be long enough to give activating species during the reaction period. Peroxides with a short half-life, S as bfinloyl checked against time. With the selection of a proper peroxide, higher temperatures for a shorter period of time may be employed. The reaction proceeds more rapidly under a blanket of inert gas such as nitrogen.

. The molar ratio of reactants is not critical to initiation of the reaction, but for optimum yields it is preferable to employ an excess of the dialkyl phosphonate. Thisis readily recovered in the product-isolation process and can be reused.

The trialkyl 9(10)-phosphonostearates of Examples 1 to 7 were incorporated into compositions for evaluation as plasticizers. A commercial copolymer (Vinylite VYDR) containing parts by weight of vinyl chloride and 5 parts by weight of vinyl acetate was used for these evaluations. mers can be used, such as, poly(vinyl chloride), poly ('vinyl chloride acetate) containing more than 5% acetate or vinyl chloride copolymers with vinyliclene chloride.

EXAMPLE 9 Trimethyl 9(10)-phosphonostearate (34 parts by weight),'copolymer (VYDR) (64 parts by weight), with 1 part by weight each of commercial stabilizers [Epoxidized Soybean Oil and Advance Solvents and Chem. Corp. 52 '(Organotin)] were milled. 'l he phosphonostearate was readily compatible with the vinyl chloride copolymer. A portion of standard thickness milled sheet (0.002 inch thick) was prepared for determination of volatility and migration characteristics. The remainder of the milled composition was molded at 300 F. Test specimens were taken from a 6 x 6 x 0.075 inch molded sheet. The tests were made by a standard ASTM methods and the results are summarized in Table II.

Trialkyl 9'(10)-phosphonostearates of Examples 2 to 7 were milled and molded exactly as described in Example 9 and the results of the evaluation tests are included in Table II as Examples 10 to 15 respectively.

For comparative purposes some commercial plastisizers were also milled and molded as in Example 9 and the Other vinyl chloride polymers and copolyresults of evaluation of these compositions are also included in Table II.

Table II COMPARISON OF PROPERTIES OF COMMERCIAL COPOLYMER (VYDR) PLASTICIZED WITH LONG CHAIN PHOSPHORUS COMPOUNDS AND COMMERCIAL PLASTICIZERS Migra- Clashtion, Vola- Ex. Tensile Elonga- Modulus Berg percent tility, N0. Compound strength, tion, T-200, weight weight I p.s.i. percent p.s.i. 0 loss loss,

after 14 percent days 1 9 Trimethyl phosphonostearate 2, 900 345 1, 200 31 8 2. 1 Triethyl phosphonostearate. 2, 700 345 1, 350 38 8 2. 0 11 Tributyl phosphonostearate 2, 700 360 1, 350 46 8 1.6 Tri(2-ethylhexyl) phosphonostearate. 3, 000 310 1, 700 48 8 2. 1 13 Ethyl dibutylphosphonostearate 2, 850 340 1, 400 41 8 1. 5 Butyl diethylphosphonostearate 2, 750 360 1, 350 45 9 1. 1 Z-ethylhexyl diethylphosphonostearate 2, 900 370 l, 450 41 9 1. 0

COMMERCIAL CONTROLS Di(2-ethylhexyl)phthalatc (DOP) 2, 950 370 1, 400 28 6 1. 1 Di(2-ethylhexyl)sebacate (D OS) 2, 600 400 1, 200 59 23 2.0 Tri(2-ethylhexyl) phosphate (TOP) 2, 600 390 1, 275 60 17 3. 6 Tricresyl phosphate (TCP) 3, 600 270 2, 000 1 0. 5 0. 3

1 A weight loss of 15% means that 54X100 or 44% of the original quantity of plasticizer has migrated out o! the sheet into the silicic acid adsorbent.

The products of the present invention are efficient plasticizers, as shown by the figures for 100% modulus.

Among plasticizers commercially available for low tempe-ra-ture use, for example (DOS) and (TOP), this valuable characteristic cannot be fully utilized because of their high migration loss. Blending these plasticizers with a non-migrating plasticizer such as (TCP) detracts from the low temperature flexibility of the plasticized poly(vinylchloride).

The plasticizing characteristics of the trialkyl 9(10)- phosphonostearates (Examples 9 to 15) are outstanding. They not only have a low migration loss (8 to 9%), but they impart good low temperature flexibility characteristics to poly(vinyl chloride) products (Examples 11 to 15 are in the 40 to 50 range). This desirable combination of characteristics has not been observed previously with any known plasticizer or combinations thereof.

We claim:

1. A flexible composition comprising polymerized vinyl chloride and, as a plasticizer therefor, about 35% by Weight of a compound selected irom the group of formulas consisting of References Cited in the file of this patent UNITED STATES PATENTS Swern Dec. 6, 1960 OTHER REFERENCES Swern et al.: Chemical and Engineering Data Series, volume 3, N0. 2, October 1958, page 346. 260-306. 

1. A FLEXIBLE COMPOSITION COMPRISING POLYMERIZED VINYL CHLORIDE AND, AS A PLASRICIZER THEREFOR, ABOUT 35% BY WEIGHT OF A COMPOUND SELECTED FROM THE GROUP OF FORMULAS CONSISTING OF 